All of the following statements about periodic trends are true, EXCEPT?

• A. Atomic size and metallic property share the same periodic trend
• B. Electronegativity decreases from top to bottom of the periodic table
• C. Ionization energy decreases from right to left of the periodic table
• D. Electron affinity increases from top to bottom of the periodic table

Answer: (D)

Periodic trends describe how properties like atomic size, metallic character, electronegativity, ionization energy, and electron affinity change as you move across periods and down groups. Atomic size grows as you go down a group and shrinks across a period; metallic character follows the same pattern, increasing down a group and decreasing across a period. Electronegativity decreases down a group and increases across a period. Ionization energy generally increases across a period and decreases down a group, so moving from the right to the left across a period lowers ionization energy—this matches the statement. Electron affinity tends to become less favorable down a group (it generally decreases), while across a period it tends to increase from left to right, with halogens showing especially large negative values.

The claim that electron affinity increases from top to bottom is not correct; the opposite downward trend is the usual one, making this the exception.